This disclosure relates in general to image cropping and, but not by way of limitation, to image cropping of book scans amongst other things.
Book scanners enable rapid scanning of books without damaging the book's binding. Some book scanners, such as those produced by Kirtas, use jets of air and a mechanical suction device to automatically turn the pages of the book, timed in synchronization with two cameras that photograph both open pages of the book. As the pages are turned, the book's position is adjusted to compensate for the amount of binding on one side or the other of the open pages. The compensation is intended to be linear and largely automatic, but in practice, manual adjustments are sometimes required to keep the book positioned optimally. To avoid missing any content, the cameras are positioned and focused so that they image the appropriate page and part of the other open page and some surrounding machinery.
In some book scanning applications the images may need cropping prior to being presented to an OCR (Optical Character Recognition) engine or a customer. The cropping keeps the OCR engine from recognizing content on the wrong page and keeps the image size smaller for faster downloads and for more aesthetically pleasing images for the customer.
A cropping rectangle could be specified manually for each image, but doing so adds a tremendous cost. There are some automated cropping tools that have been used, but such tools tend to crop too much or too little from the images.
Accordingly, there is a need in the art to provide a cropping tool that quickly and properly crops unwanted portions of a scanned image.